• Clean Technology
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• v.23 no.3
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• pp.286-293
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• 2017

The goal of this paper was to improve the performance of the adsorbent to remove $H_2S$. Pellet type adsorbents were prepared by using four kinds of materials ($Fe_2O_3$, $Ca(OH)_2$, Activated carbon, $Al(OH)_2)$ for use as a basic carrier. As the results of $H_2S$ adsorption tests, $Fe_2O_3$ and Activated Carbon improved the adsorption performance of $H_2S$ by 1.5 ~ 2 times, and $Ca(OH)_2$ and $Al(OH)_2$ showed no effect on $H_2S$ adsorption performance. Four basic materials were as carriers, and 5 wt% of KI, KOH and $K_2CO_3$ were added on the carriers, respectively. As the results of $H_2S$ adsorption tests, adsorbent containing $K_2CO_3$ showed the best performance. As a result of $H_2S$ adsorption test with varying $K_2CO_3$ content from 5 to 30 wt%, it was confirmed that adsorption performance was increased up to 20 wt% of $K_2CO_3$ and adsorption performance decreased to 30 wt%. The $H_2S$ adsorption performance was modeled by using Thomas model with varying $K_2CO_3$ contents and the results were used for the adsorption tower design. It was shown that the experimental values and the simulated values were in good agreement with the contents range of $K_2CO_3$ up to 20 wt%. Based on these results, it is expected that not only the adsorption performance of $H_2S$ adsorbent is improved but also life time of the adsorbent is increased.

• Carbon letters
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• v.10 no.3
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• pp.221-224
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• 2009

In this work, the $CO_2$ adsorption behaviors of amine functionalized activated carbons (ACs) were investigated. The surface of ACs was modified with urea, melamine, diethylenetriamine (DETA), pentaethylenehexamine (PEHA), polyethylenimine (PEI), and 3-aminopropyl-triethoxysilane (ATPS). The various surface properties of amine functionalized ACs were characterized by Boehm's method, nitrogen full isotherms, XPS, and TGA analyses. The active ingredients impregnated on the ACs show significant influence on the adsorption for $CO_2$ and its volumes adsorbed on amine functionalized ACs are larger than that on the pristine ACs, which is due to the grafted amine groups of the AC surfaces.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3022-3026
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• 2013

The adsorption of carbon dioxide on graphene sheets was theoretically investigated using density functional theory (DFT) and MP2 calculations. Geometric parameters and adsorption energies were computed at various levels of theory. The $CO_2$ chemisorption energies on graphene-$C_{40}$ assuming high pressure are predicted to be 71.2-72.1 kcal/mol for the lactone systems depending on various C-O orientations at the UCAM-B3LYP level of theory. Physisorption energies of $CO_2$ on graphene were predicted to be 2.1 and 3.3 kcal/mol, respectively, at the single-point $UMP2/6-31G^{**}$ level of theory for perpendicular and parallel orientations.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.257-264
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• 2008

Adsorption is one of the most efficient method for the separation of low level carbon dioxide. In order to enhance the adsorption capacity, a few additives such as alkali hydroxides were combined with the zeolitic sorbents. As a result of the experimental examination by applying the $CO_2$ flow of 3000 ppm, the composite sorbent showed the improved quality to a certain degree and the added binder was also found to contribute to better adsorption.

• Journal of the Mineralogical Society of Korea
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• v.11 no.1
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• pp.20-31
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• 1998

Adsorption of metal elements onto illite and halloysite was investigated at $25^{\circ}C$ using pollutant water collected from the gold-bearing metal mine. Incipient solution of pH 3.19 was reacted with clay minerals as a function of time: 10 minute, 30 minute, 1 hour, 12 hour, 24 hour, 1 day, 2 day, 1 week, and 2 week. Twenty-seven cations and six anions from solutions were analyzed by AAs (atomic absorption spectrometer), ICP(induced-coupled plasma), and IC (ion chromatography). Speciation and saturation index of solutions were calculated by WATEQ4F and MINTEQA2 codes, indicating that most of metal ions exist as free ions and that there is little difference in chemical species and relative abundances between initial solution and reacted solutions. The adsorption results showed that the adsorption extent of elements varies depending on mineral types and reaction time. As for illite, adsorption after 1 hour-reaction occurs in the order of As>Pb>Ge>Li>Co, Pb, Cr, Ba>Cs for trace elements and Fe>K>Na>Mn>Al>Ca>Si for major elements, respectively. As for halloysite, adsorption after 1 hour-reaction occurs in the order of Cu>Pb>Li>Ge>Cr>Zn>As>Ba>Ti>Cd>Co for trace elements and Fe>K>Mn>Ca>Al>Na>Si for major elements, respectively. After 2 week-reaction, the adsorption occurs in the order of Cu>As>Zn>Li>Ge>Co>Ti>Ba>Ni>Pb>Cr>Cd>Se for trace elements and Fe>K>Mn>Al, Mg>Ca>Na, Si for major elements, respectively. No significant adsorption as well as selectivity was found for anions. Although halloysite has a 1:1 layer structure, its capacity of adsorption is greater than that of illite with 2:1 structure, probably due to its peculiar mineralogical characteristics. According to FTIR (Fourier transform infrared spectroscopy) results, there was no shift in the OH-stretching bond for illite, but the ν1 bond at 3695 cm-1 for halloysite was found to be stronger. In the viewpoint of adsorption, illite is characterized by an inner-sphere complex, whereas halloysite by an outer-sphere complex, respectively. Initial ion activity and dissociation constant of metal elements are regarded as the main factors that control the adsorption behaviors in a natural system containing multicomponents at the acidic condition.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.396-400
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• 2010

In this work, the adsorption behaviors of activated carbons (ACs) containing chelating functional groups were studied in $CO_2$ removal. The ACs were modified by pyrolysis of peroxide and glycidyl methacrylate graft polymerization in order to induce chelating functional groups, such as diethylenetriamine groups on the AC surfaces. The surface functional groups of the ACs were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The textural properties of the ACs were analyzed by $N_2$/77 K isotherms. Adsorption behaviors of the ACs were observed in the amounts of $CO_2$ adsorption. From the results, we found that the chelating functional groups on the AC surfaces led to enhance selectivity and chemisorption on $CO_2$ adsorption in spite of decreasing the physical adsorption properties.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.80-85
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• 2016

The carbon dioxide adsorption behavior of silica with a large specific surface area and pore volume functionalized with aminosilane compounds via in-situ polymerization and functionalization method were investigated. The organosilanes include amino functional group capable of adsorbing carbon dioxide. Elemental analyzer, in situ FT-IR and thermogravimetric analyzer were used to characterize the sorbents and to determine their $CO_2$ adsorption behavior. Comparison of different aminosilane loading in the support revealed that polyaminosilane functionalization of 70% of the pore volume in the support was better in terms of the adsorption capacity and amine efficiency than that of 100% of the pore volume of the support. Furthermore, the sorbents showed a higher adsorption capacity at an adsorption temperature of $75^{\circ}C$ than at $30^{\circ}C$ due to the thermal expansion of synthesized polyaminosilanes inside the pore of silica. The N-[3-(trimethoxysilyl)propyl]ethylenediamine (2NS) sorbent with 70% of the pore volume functionalized showed the highest adsorption capacity of 9.2 wt% at $75^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.941-946
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• 2009

Two types of synthetic zeolites, commercially used (Z-WK) and synthesized by coal fly ash (Z-C1), and raw coal fly ash(F-C1) were examined for its kinetics and adsorption capacities of cobalt. Experimental data are fitted with kinetic models, Lagergen $1^{st}$ and $2^{nd}$ order models, and four types of adsorption isotherm models, Langmuir, Freundlich, Redlich-Peterson, and Koble-Corrigan. Synthesized zeolite (Z-C1) which had 1.51 of Si/Al ratio was synthesized by raw coal fly ash from a thermal power plant. Adsorption capacities with three types of adsorbents, Z-WK, Z-C1, and F-C1, were in the order of Z-C1 (94.15 mg/g) > F-C1 (92.94 mg/g) > Z-WK (88.56mg/g). The adsorption kinetics of Z-WK and Z-C1 with cobalt could be accurately described by a pseudo-second-order rate equation. The adsorption isotherms of Z-WK and Z-C1 with cobalt were well fitted by the Langmuir and Redlich-Peterson equation. Z-C1 will be used to remove cobalt in water as a more efficient absorbent.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.402-409
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• 2001

Different bioligands carrying synthetic adsorbents have been reported in the literature for protein separation, We have developed a novel and new approach to obtain high protein ad-sorption capacity utilizing 2-methacrylamidohistidine(MAH) as a bioligand. MAH was synthe-sized by reacting methacrylocholride and histidine, Spherical beads with an average size of 150-200㎛ were obtained by the radical suspension polymerization of MAH and 2-hydrosyethyl-methacrylate(HEMA) conducted in an aqueous dispersion medium. p(HEMA-co-MAH) beads had a specific surface area of 17.6㎡/g . Synthesized MAH monomer was characterized by NMR. p(HEMA-co-MAH) beads were characterized by swelling test, FTIR and elemental analysis. Then Cu(II) ions were incorporated onto the beads and Cu(II) loading was found to be 0.96 mmol/g.These affinity beads with a swelling ration of 65% and containing, 1.6 mmol MAH/g were used in the adsorption/desorption of human serum albumin(HSA) from both aqueous solutions and hu-man serum. The adsorption of HSA onto p(HEM-co-MAH) was low(8.8 mg/g). Cu(II) chelation onto the beads significantly increased the HSA adsorption (56.3 mg/g). The maximum HSA ad-sorption ws observed at pH 8.0 Higher HSA adsorption was observed from human plasma(94.6 mgHSA/g) Adsorption of other serum proteins were obtained as 3.7 mg/g for fibrinogen and 8.5mg/g for γ-globulin. The total protein adsorption was determined as 107.1mg/g. Desorption of HSA was obtained using 0.1 M Tris/HCl buffer containing 0.5 M NaSCN, High desorption rations(up to 98% of the adsorbed HSA) were observed. It was possible to reuse Cu(II) chelated-p(HEMA-co-MAH) beads without significant decreases in the adsorption capacities.

• Korean Journal of Materials Research
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• v.26 no.6
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• pp.298-305
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• 2016

In this work, recent progress on graphene/metal oxide composites as advanced materials for $HgCl_2$ and $CO_2$ capture was investigated. Density Functional Theory calculations were used to understand the effects of temperature on the adsorption ability of $HgCl_2$ and water vapor on $CO_2$ adsorption on CaO (001) with reinforced carbon-based nanostructures using B3LYP functional. Understanding the mechanism by which mercury and $CO_2$ adsorb on graphene/CaO (g-CaO) is crucial to the design and fabrication of effective capture technologies. The results obtained from the optimized geometries and frequencies of the proposed cluster site structures predicted that with respect to molecular binding the system possesses unusually large $HgCl_2$ ($0.1-0.4HgCl_2g/g$ sorbent) and $CO_2$ ($0.2-0.6CO_2g/g$ sorbent) uptake capacities. The $HgCl_2$ and $CO_2$ were found to be stable on the surface as a result of the topology and a strong interaction with the g-CaO system; these results strongly suggest the potential of CaO-doped carbon materials for $HgCl_2$ and $CO_2$ capture applications, the functional gives reliable answers compared to available experimental data.